Semiconductor devices are essential for many modern applications. With the advancement of electronic technology, semiconductor devices are becoming smaller in size while having greater functionality and greater amounts of integrated circuitry. Due to the miniaturized scale of semiconductor devices, chip-on-chip technique is now widely used for manufacturing semiconductor packages.
In one approach, using a stack of at least two chips (or dies), in a 3D package to form, for example, a memory device, it is possible to produce a product having a memory capacity which is twice as large as that obtainable through other semiconductor integration processes. In addition to the increase in memory capacity, a stack package also provides improved mounting density and mounting area utilization efficiency. Due to such advantages, research and development of stack package technology has accelerated.
One type of a stack package using a through-silicon via (TSV) has been disclosed in the art. The stack package using a TSV has a structure in which the TSV is disposed in a chip so that chips are electrically connected to each other through the TSV. Generally, a TSV is formed by etching a vertical via through a substrate and filling the via with a conductive material, such as copper (Cu). Usually, vertical vias formed through the substrate have a same depth and are aligned with pads formed in the chip. Further, specific routing lines are designed and formed to serve as the terminals on which the TSVs are disposed. However, such specific routing lines complicate the circuit design, especially in dual-die stacking.
This Discussion of the Background section is for background information only. The statements in this Discussion of the Background are not an admission that the subject matter disclosed in this section constitutes a prior art to the present disclosure, and no part of this section may be used as an admission that any part of this application, including this Discussion of the Background section, constitutes prior art to the present disclosure.